Affordable Access To Space – Getting There

To realise the full potential of modern low cost mini-micro-nano-satellite missions, regular and affordable launch opportunities are required. It is simply not economic to launch satellites of 5-300kg on single dedicated launchers costing typically $10-20M per launch. Whilst there have been periodic \u27piggy-back\u27 launches of small satellites on US launchers, these have been infrequent and often experienced significant delays due the vagaries of the main (paying!) payload. In 1988, Arianespace provided a critical catalyst to the microsatellite community when it developed the ASAP platform on Ariane-4 providing, for the first time, a standard interface with affordable commercial launch contracts for small payloads up to 50kg. Some 20 small satellites have since been launched on the Ariane-4 ASAP ring, however as most of these microsatellite missions seek low Earth orbit (especially sun-synchronous) the number of prime missions into these orbit has declined since 1996 and with it the useful low cost launch opportunities for microsatellites. Whilst Ariane-5 has an enhanced capacity ASAP, it has yet to be widely used due to the infrequent launches, higher costs, and the unpopularity of the GTO orbit required by the majority of customers. China, Japan and India have also provided occasional launches for small payloads, but not yet on a regular basis. Fortunately, the growing interest and demand for microsatellites coincided with the emergence of regular, low cost launch opportunities from the former Soviet Union (FSU) - both as secondary \u27piggy-back\u27 missions or as multiple microsatellite payloads on converted military ICBMs. Indeed, the FSU now supplies the only affordable means of launching minisatellites (200-500kg) into LEO as dedicated missions on converted missiles as these larger \u27small satellites\u27 are often too big to be carried \u27piggy-back\u27. The entrepreneurial effort of leading FSU rocket & missile organisations has taken over providing launches for the small satellite community with an excellent track record. However, negotiating and completing a Launch Services Contract for a micro-minisatellite with any launcher organisation is a complex matter and risky territory for the unwary or inexperienced - who may fall prey to unexpected costs and delays. Whilst this warning should be heeded when dealing with European and US organisations, it is particularly relevant to negotiating launches from the FSU where there is a plethora of agencies and organisations providing a bewildering range of launch vehicles and options. Furthermore, the FSU has developed a very different technical and managerial philosophy towards launchers when compared with the West and this can be unnerving to \u27first-time buyers\u27. Organisations experienced in dealing in the FSU will encounter an excellent service - once the launch service agreement has been thoroughly and fiercely negotiated in every detail. Inexperienced buyers have encountered delays, lost opportunities, unexpected taxes, additional cost for services or facilities not originally specified, and frustration at the different procedures used in the FSU. Fortunately, all this can be avoided and the FSU is the current mainstay for launching small satellites quickly, affordably and reliably. SSTL has unique experience gathered over 22 years in handling launches for small satellites, ranging from a 6kg nanosatellite, 50-120kg microsatellites, and a 325kg minisatellite, using 7 different launchers from the USA, Russia, Ukraine, and Europe. This experience, and working closely with organisations in the FSU, has enabled SSTL to provide good value launches for its small satellite customers without delay and with an excellent launch success. The paper will describe the experience gained by Surrey, across the various launch providers, in successfully launching 21 small satellites - affordably, reliably and quickly. It will highlight the key factors that are necessary to ensure a \u27good experience\u27

One Year in Space: Results from PoSAT-1

PoSAT-1 was launched in September 1993, joining the UoSAT family of spacecraft already in orbit. Built by Surrey Satellite Technology Ltd. (SSTL) for a consortium of Portuguese industry, PoSAT-1 represents the latest generation of UoSAT microsatellites. This paper will briefly review the development and evolution of the UoSAT design. It will then summarize key functional parameters of PoSAT-1 including attitude determination and control, electrical power, data handling systems, thermal control and communications. PoSAT-1 contains a variety of experiments including CCD wide and narrow field Earth imaging cameras, a star field sensor, a GPS receiver, cosmic radiation and total radiation dose detectors, and a digital signal processing (DSP) experiment. Results from all these experiments will be highlighted. The paper concludes with future UoSAT/SSTL research and development efforts

In-situ particle sizing of agglomerates in aluminized solid composite propellants using digital inline holography (DIH)

Aluminized ammonium perchlorate composite propellants (APCP) form large molten agglomerated particles that can result in poor combustion performance and increased two-phase flow losses. Quantifying agglomerate size distributions is important for assessing these losses for different types of aluminum fuels that can help improve rocket performance. It is highly desirable to measure particle sizes in-situ using non-intrusive optical methods, rather than conventional particle collection, which can have large uncertainties. Regular high-speed microscopic imaging suffers from a limited depth of field. Digital inline holography (DIH) is an alternative approach that results in 3D information through numerical reconstruction. In this paper, DIH approach was used with two orthogonal viewing angles for simultaneous particle imaging and velocity measurements. Furthermore, two imaging speeds (4 Hz vs. 4,000 Hz) were compared to characterize biasing. DIH results were contrasted with high-speed visual imaging and conventional particle collection. All techniques were in agreement that ejected particles were larger than initial constituent particles. However, DIH allows for the acquisition of much less experimental data for statistically significant data sets when compared to videography and more accurately sizes agglomerates than particle collection. Low-speed DIH is found to be subject to biasing due to multiple counting of larger particles with slower velocities staying in the field of view. A model was employed to correct the velocity biasing was performed by adjusting the data based on size and velocity correlations. This was partially successful to reduce biasing of sizes for the low speed DIH data

A Nanosatellite to Demonstrate GPS Oceanography Reflectometry

This paper describes a proposal for a rapid, low cost, nanosatellite mission to demonstrate the concept of GPS ocean reflectometry and to investigate the feasibility of determining sea state for a future operational space-based storm warning systems. The aims of this mission are to prove the general feasibility of GPS ocean reflectometry, to demonstrate sea state determination and to enable the development of a practical GPS ocean reflectometry payload for future missions. The payloads on the satellite consist of a 24 channel C/A code SGR-10 space GPS receiver and a solid state data recorder. The GPS receiver has one standard RHCP zenith antenna, and one high gain LHCP nadir antenna for receiving the reflected signals. A dual approach is taken to measurement gathering. Initially, bursts of directly sampled IF data are stored and downloaded to permit processing of the data on the ground. Later in the mission, the GPS receiver software may be modified to permit the processing of signals on-board the satellite. The nanosatellite is based on SSTL’s SNAP design and has a projected total mass of around 12 kilograms; orbit average power of approximately 4.8 watts; 3-axis attitude control to 1-2 degrees; VHF uplink, S-band downlink at 500 kbps, and OBC based on the StrongARM SA1100. Using the SNAP design enables a fast manufacture at low cost: estimated at 9 months and around 2 million Euros, including launch. The proposed mission makes use of the Surrey Space Centre Mission Control ground-station in Guildford (UK) for control and data gathering. Surrey Satellite Technology Ltd (SSTL) is a world leader in both nanosatellite and GPS technology for small satellites. SSTL’s highly successful SNAP-1 nanosatellite launched in June 2000 demonstrated the potential of such small spacecraft, and this proposal involves the first ever use of a nanosatellite for a commercial application (GANDER) in collaboration with SOS Ltd (UK) a company specialising in oceanography from space

Low Cost Hyperspectral Imaging From a Microsatellite

A 100 kg class SSTL microsatellite platform accommodating the Sira Compact High Resolution Imaging Spectrometer (CHRIS) can perform high spectral resolution imaging over multiple wavelengths. Hyperspectral imaging data may be used within a wide variety of applications ranging from precision agriculture and land use, to ocean colour monitoring, coastal and atmospheric studies. CHRIS operates in the 415 to 1050 nm wavelength band, with spectral sampling interval from 2 to 12 nm (depending on wavelength) and is programmable from the ground. Operating at 25 m ground sample distance the instrument can provide information over 19 spectral bands whilst at 50 m ground sample distance, for example, 63 bands can be imaged simultaneously. Flying CHRIS as the main payload on a SSTL microsatellite enables dedicated platform resources to exploit the huge potential of such a payload at low cost. The three-axis stabilised platform can off-point from nadir by ±30° to support accurate target selection. 48 Mbps payload data downlink rates, a 12 Gbyte data storage, and high efficiency GaAs panels for power provision all ensure a good payload duty cycle per orbit. The estimated spacecraft cost is 8.5 million GBP, resulting in affordable constellation options. A constellation of hyperspectral satellites providing high temporal resolution in addition to high spectral resolution could also be used to enhance the infrastructure of the Disaster Monitoring Constellation (DMC). The DMC is currently under construction at SSTL and is due for launch in 2002. This may be implemented either singly, or in constellations, via a ‘plug and play’ constellation approach. This paper describes how low cost hyperspectral imaging may be effectively accomplished using a microsatellite platform and looks at the potential benefits of implementing a series of these microsatellites in a constellation

VISTA – A Constellation for Real Time Regional Imaging

The role of satellites in medium and high-resolution reconnaissance of the Earth has been well demonstrated in recent years through missions such as Landsat, SPOT, IKONOS, ImageSat and Quickbird. The market for such data products is well served and likely to become more competitive with further very-high-resolution missions. Whereas commercial markets have concentrated on enhancing resolution, the small satellite sector has concentrated on reducing the cost of data products, and the development of systems providing niche services. One such area that can be well served by smaller satellites is the need for higher temporal resolution, as this typically requires a large number of satellites to operate as a constellation. Surrey is currently engaged in building its first constellation providing daily global coverage at moderate resolution in three spectral bands. Targeted at providing timely quick-look data products for disaster mitigation and monitoring, the constellation comprises 5 satellites in a single orbital plane. Each satellite has a wide swath so that successive satellites progressively cover the entire globe in a single day. The Vista constellation takes this concept a step further, and is proposed for applications requiring near-continuous surveillance of regional activity. By introducing a multiple plane constellation of small Earth Observation satellites, it is possible to monitor the entire globe continuously. The paper describes the system trades and outlines the scope of the performance that could be obtained from such a system. A cost model illustrates that the balance between launch and space segment costs must be reached by considering suitable replacement strategies, and that the system is highly sensitive to requirement creep. Finally, it is shown that the use of cost effective, small satellites leads to solutions previously thought to be out of reach of government customers

Effectiveness of life skills training on increasing self-esteem of high school students

AbstractObjective This study designed to investigate effectiveness of training life skills on adolescents’ students. Method This study is a pseudo-experimental study which accomplished on 160 students in Karaj city. Subjects of the study selected randomly from list of students in all of the schools of Karaj; then they divided randomly in two groups. Trained counsellors taught the life skills to students of the study group, and 80 reminder subjects assigned as control group. After educating the training program, subjects administered Cooper Smith self-esteem questionnaire (58-items version). Results Findings of the study indicated that life skills training lead to significant increase of self-esteem in study group in contrast to control group subjects. Conclusion Psycho education and mental health programs such as life skills training could cause to increase the necessary skills in students and decline school and educational problems

Open hiring™ Een baan zonder sollicitatiegesprek

Wat gebeurt er als je de deuren van je bedrijf openzet voor iedereen? Als je mensen niet selecteert via uitgebreide sollicitatieprocedures, maar gewoon een kans geeft, zonder vooraf vragen te stellen? Het Amerikaanse bedrijf Greyston werkt al meer dan dertig jaar volgens dit principe. Zij noemen het open hiring. Start Foundation investeert nu in de toepassing van dit concept door Nederlandse werkgevers. Welke potentie heeft open hiring op de Nederlandse arbeidsmarkt

Constella, a Quick Configuration Platform for Rapid Response Missions

Constella is a novel very quick response satellite platform that can be used in any Low Earth Orbit, It can be used as a single unit or as part of a constellation of spacecraft. It can be pre-manufactured to a large extent, and a selection of subsystems can be ready to select from, to provide last-minute configuration options for both the payload and platform. This satellite contains a number of innovations that have not been used in space before, and they will allow very quick response missions to take place. Only a very short time is required to decide on the mission and plan the satellite design, then assemble the final parts, and test and launch the satellite into orbit. The total time can be down to weeks or even days. Unlike most quick-response missions, where anything under one year is included, and where the satellite typically has to be completely ready and tested, waiting for quick call-up, the Constella can be tailored with interchangeable attitude sensors, propulsion units, communications equipment, payloads and more, just before launch, even right at the launch site if required. The platform produces almost the same amount electrical power, irrespective of orbital inclination or ascending node time, removing the need for solar panel design changes at the configuration stage.</p

Constella, a Quick Configuration Platform for Rapid Response Missions

Constella is a novel very quick response satellite platform that can be used in any Low Earth Orbit, It can be used as a single unit or as part of a constellation of spacecraft. It can be pre-manufactured to a large extent, and a selection of subsystems can be ready to select from, to provide last-minute configuration options for both the payload and platform. This satellite contains a number of innovations that have not been used in space before, and they will allow very quick response missions to take place. Only a very short time is required to decide on the mission and plan the satellite design, then assemble the final parts, and test and launch the satellite into orbit. The total time can be down to weeks or even days. Unlike most quick-response missions, where anything under one year is included, and where the satellite typically has to be completely ready and tested, waiting for quick call-up, the Constella can be tailored with interchangeable attitude sensors, propulsion units, communications equipment, payloads and more, just before launch, even right at the launch site if required. The platform produces almost the same amount electrical power, irrespective of orbital inclination or ascending node time, removing the need for solar panel design changes at the configuration stage.</p